Fabrication of electrically conductive elastomers using multi-walled carbon nanotubes and liquid metal.

Electrically conductive elastomers, composite materials made of flexible polymers and conductive fillers, are highly desirable for the development of flexible electronics. Of particular interest is the potential to use a conductive elastomer in the development of flexible capacitors. The objective of this project is to fabricate various conductive elastomers using multi-walled carbon nanotubes (MWCNTs) and liquid metal as the conductive fillers with polyurethane as the flexible polymer. MWCNTs and liquid metal have high electrical conductivity while polyurethane is a good insulator due to high dielectric strength. Two fabrication techniques will be attempted. The first involves dissolving polyurethane beads in N,N-Dimethylformamide (DMF) and adding MWCNTs that are aligned using a suitable electrical field. This solution will form into a block for conductivity testing. The other technique involves injecting liquid metal into 0.127mm (inner diameter) polyurethane tubing which is coated in a solution of polyurethane and MWCNTs. This will form a multilayer conductive elastomer composite which is expected to have some properties of a flexible capacitor. From these techniques, optimal parameters for fabrication can be determined and the electrical conductivity and elasticity of the composites can be tested. Creating highly flexible conductive composites may lead to development in fields of flexible robotics, wearable electronics, strain sensors, and dielectric actuators